from django.shortcuts import render, redirect, get_object_or_404

from django.contrib.auth.decorators import login_required

from .models import Topic, Entry

from .forms import TopicForm, EntryForm

from django.http import Http404


# 在这里创建视图.
def index(request):
	return render(request, 'learning_logs/index.html')

@login_required
def topics(request):
	"""显示所有的主题"""
	topics = Topic.objects.filter(owner=request.user).order_by('date_added')
	context = {'topics': topics}
	return render(request, 'learning_logs/topics.html', context)

@login_required
def topic(request, topic_id):
	"""显示单个主题及其所有的条目"""
	topic = get_object_or_404(Topic, id=topic_id)
	#确认请求的主题属于当前用户。
	if topic.owner != request.user:
		raise Http404
	entries = topic.entry_set.order_by('-date_added')
	context = {'topic': topic, 'entries': entries}
	return render(request, 'learning_logs/topic.html', context)

@login_required
def new_topic(request):
	"""添加新主题"""
	if request.method != 'POST':
		#未提交数据：创建一个新表单。
		form = TopicForm()
	else:
		#POST提交数据：对数据进行处理。
		form =TopicForm(data=request.POST)
		if form.is_valid():
			new_topic = form.save(commit=False)
			new_topic.owner = request.user
			new_topic.save()
			return redirect('learning_logs:topics')
	#显示空表单或指出表单数据无效。
	context = {'form': form}
	return render(request, 'learning_logs/new_topic.html', context)

@login_required
def new_entry(request, topic_id):
	"""在特定主题中添加新条目"""
	topic = Topic.objects.get(id=topic_id)

	if request.method != 'POST':
		#未提交数据：创建一个空表单。
		form = EntryForm()
	else:
		#POST提交的数据：对数据进行处理。
		form = EntryForm(data=request.POST)
		if form.is_valid():
			new_entry = form.save(commit=False)
			new_entry.topic = topic
			new_entry.save()
			return redirect('learning_logs:topic', topic_id=topic_id)
	#显示空表单或指出表单数据无效。
	context = {'topic': topic, 'form': form}
	return render(request, 'learning_logs/new_entry.html', context)

@login_required
def edit_entry(request, entry_id):
	"""编辑既有条目"""
	entry = Entry.objects.get(id=entry_id)
	topic = entry.topic

	#确认请求的编辑条目属于当前用户。
	if topic.owner != request.user:
		raise Http404

	if request.method != 'POST':
		#初次请求：使用当前条目填充表单。
		form = EntryForm(instance=entry)
	else:
		#POST提交的数据：对数据进行处理。
		form = EntryForm(instance=entry, data=request.POST)
		if form.is_valid():
			form.save()
			return redirect('learning_logs:topic', topic_id=topic.id)

	context = {'entry': entry, 'topic': topic, 'form': form}
	return render(request, 'learning_logs/edit_entry.html', context)
